i hope you can help me. I am running several Linux Containers on a bare metal server which is provided with an Global Ipv6 address as well as an 64-bit network by my provider.

I have configured IPv6 settings within the config files of each container using a bridge provided by the host machine. When I reboot the whole system I am able to access my containers via IPv6 and vice versa (e.g. ping6 google.de works). After some time (dunno how long) the containers are no more accessible via their ipv6-address and I don't know why (ping6 google.de also doesn't work). Does anyone have a clue what could cause this behavior?

Here are my configs:

network/interfaces (master)

iface br0 inet6 static pre-up modprobe ipv6 address 2a02:xxxx:1:1::517:f79 gateway 2a02:xxxx:1:1::1 netmask 64 bridge_stp on

sysctl.conf (master)

ipv6 settings (no autoconfiguration)

net.ipv6.conf.default.autoconf=0 net.ipv6.conf.default.accept_ra=0 net.ipv6.conf.default.accept_ra_defrtr=0 net.ipv6.conf.default.accept_ra_rtr_pref=0 net.ipv6.conf.default.accept_ra_pinfo=0 net.ipv6.conf.default.accept_source_route=0 net.ipv6.conf.default.accept_redirects=0 net.ipv6.conf.default.forwarding=1 net.ipv6.conf.default.proxy_ndp=1 net.ipv6.conf.all.autoconf=0 net.ipv6.conf.all.accept_ra=0 net.ipv6.conf.all.accept_ra_defrtr=0 net.ipv6.conf.all.accept_ra_rtr_pref=0 net.ipv6.conf.all.accept_ra_pinfo=0 net.ipv6.conf.all.accept_source_route=0 net.ipv6.conf.all.accept_redirects=0 net.ipv6.conf.all.forwarding=1 net.ipv6.conf.all.proxy_ndp=1

network/interfaces (container)

The loopback network interface

auto lo iface lo inet loopback

auto eth0 iface eth0 inet manual iface eth0 inet6 manual

LXC-Container config

Network configuration

  • lxc.network.type = veth
  • lxc.network.flags = up
  • lxc.network.link = br0
  • lxc.network.hwaddr = 7e:7f:de:16:xx:xx
  • lxc.network.ipv4.gateway = 81.7.xx.1
  • lxc.network.ipv4 = 81.7.xx.xxx/24
  • lxc.network.ipv6 = 2a02:xxxx:a:77::123/64

I would be very thankful for any advice.

Best, Patrick

  • Is this on Hetzner or another provider? Jul 1, 2015 at 18:10
  • It's on EUServ, but does it matter? The master server does not lose the ipv6 connection at all, only the containers :(
    – Patrick P.
    Jul 3, 2015 at 14:16
  • Yes it probably matters. Many such providers do slightly odd things to their networks that you have to work around. Hetzner is just a famous example. I'm not familiar with EUServ and my German is terrible, so I will have to leave this for someone else... Jul 3, 2015 at 16:03
  • You might want to try your set-up on Linode. This IaaS provider has a sane and reliable way of handling multi-tenant IPv6 networking. I think you'd increase your odds of people being able to help you. Jul 6, 2015 at 18:18

1 Answer 1


Try disabling multicast snooping:

echo -n 0 > /sys/class/net/<brif>/bridge/multicast_snooping

Or enabling multicast querier (very early):

echo -n 1 > /sys/class/net/<brif>/bridge/multicast_querier


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